Scrap, fundamentally, carries away a significant part of the earnings of many companies. In many sectors, the fight against scrap is still perceived as "repairing." Repair often leads to costs worse than scrap. Indeed, the severity of the situation has grown so great that the ability of some employees to repair is treated as a merit rewarded with extra pay.
As in every field, the lean production system has also brought unique solutions to scrap and repair. Fundamentally, by aiming at "zero-scrap production" and continually reducing scrap and repair, costs have been reduced, and customer and employee satisfaction have been improved.
Reducing scrap and repair, as with the other lean production techniques, first requires a cultural and conceptual change. After that, with certain practices and principles, Jidoka and Pokayoke systems and applications emerge. Below, we will touch in turn on the basic principles of these systems.
Principles for reducing scrap
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Every item of scrap occurs because of an error. In principle, preventing errors means preventing scrap. In many companies, quality control is carried out after production. In this way, one gets no further than sorting the defective production that has already been made. What should be done instead is to prevent errors by checking them before production and during production. This can be done only with 100% inspection and Pokayoke applications.
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Setups, and changes that have not been standardized, are the second important sources of scrap. Setups should be eliminated, and a transition to standard production should be achieved. (See sample applications)
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Most of the time, because employees are not aware of the scrap, they think they are working without error, or, because they do not fully understand customer requirements, they have created the notion of "good enough" by their own judgment. Feedback, discussion of the errors, and review of the methods will ensure that scrap is reduced to a large extent.
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Technical insufficiency and the lack of personal development are important sources of scrap. Training is essential, and an opportunity, for every employee. Continuous training should be company policy for scrap and repair.
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Production and order pressure is often judged incorrectly, and working with a certain amount of scrap is accepted from the outset. Yet do not forget that you will continue to produce scrap until you find the problem and remove it. For example, on a pad-printing line, instead of setting aside as scrap 20% of the product you produce because of dust, spending 15% of the time on cleaning will let you achieve the same production quantities while gaining the 20% you throw away. In other words, stopping often and cleaning the dust is cheaper.
